Welcome to Study of the Week from Patient Worthy. In this segment, we select a study we posted about from the previous week that we think is of particular interest or importance and go more in-depth. In this story we will talk about the details of the study and explain why it’s important, who will be impacted, and more.

If you read our short form research stories and find yourself wanting to learn more, you’ve come to the right place.

This week’s study is…

Can ketogenic dietary interventions slow disease progression in ADPKD: what we know and what we don’t

We previously published about this research in a story titled “Could a Ketogenic Diet Benefit Those with ADPKD?” which can be found here. The study was originally published in the scientific journal Clinical Kidney Journal. You can read the full text of the study here. 

This research team was affiliated with the UC Santa Barbara.

What Happened?

Polycystic kidney disease, and autosomal dominant polycystic kidney disease (ADPKD) in particular, is the most widespread, potentially fatal genetic disorder in humans. Biochemist Thomas Weimbs has been researching the disorder for years and made a startling discovery several years ago when he found that mice with PKD benefited from entering the metabolic state known as ketosis. More recently, his team sought to continue on this research path with a study that is assessing the real-life results of a group of ADPKD patients who have undertaken a ketogenic diet in order to induce ketosis.

Ketosis is a metabolic state of elevated levels of ketone bodies in the urine and blood. This state is a response to low availability of glucose and can be induced through fasting or a low-carbohydrate diet. Inducing ketosis intentionally through a ketogenic diet is a well established method for treating epilepsy and type 2 diabetes. 

Following the revelations from their earlier research, it wasn’t difficult for the researchers to find patients that had begun following a ketogenic diet in order to treat their ADPKD. With an estimated 500,000 patients in the US, polycystic kidney disease is not considered rare. The team found 131 ADPKD patients who were using time restricted or ketogenic diets for six months on average. They then conducted interviews with each patient, asking questions about the results and also seeking to understand any safety concerns that had been encountered.

The results were striking, with 86 percent of participants reporting health improvements after using the diet. 64 percent reported improved blood pressure and 67 percent reported improvements in issues related specifically to ADPKD. 92 percent reported their interventions as ‘feasible’ and 90 percent reported significant weight loss. 53 percent reported taking breaks from the diet, mostly for practical reasons. 66 reported adverse effects, such as elevated cholesterol and ‘keto flu,’ including fatigue and hunger. Patients following stricter ketogenic diets were more likely to experience these issues than those on time-restricted diets. However, these difficulties subsided over time and are a well known effect of ketosis.

Overall, the findings indicate that a ketogenic or time-restricted diet can be an effective management tool for ADPKD.

About Autosomal Dominant Polycystic Kidney Disease (ADPKD)

Autosomal dominant polycystic kidney disease (ADPKD) is the most widespread monogenic human disorder that can be potentially fatal. However, it is still generally rare. It is characterized by the development of cysts in the kidneys and sometimes other organs as well. ADPKD is caused by mutations affecting the PKD1 gene in 85 percent of cases; in the remainder, the mutation affects the PKD2 gene. The presentation of the disease varies considerably, even within families. Signs of kidney problems often do not appear until middle age, although cysts may begin formation very early in life. Symptoms include anemia, bloody urine, acute loin pain, uremia, liver cysts, berry aneurysm, and high blood pressure. Treatment options are varied; aquaretics can slow disease progression temporarily. Other options include a number of surgical procedures, dialysis, and, when the kidneys begin to fail, kidney transplant. To learn more about ADPKD, click here.

Why Does it Matter?

The findings reinforce the results of the earlier research using a PKD mouse model, and appear to indicate that many patients living with ADPKD and other forms of the disease can benefit from a ketogenic or time-restricted diet that induces the ketosis metabolic state.

Weimbs and his team plan to continue evaluating the effects of a ketogenic diet vs intermittent fasting in people living with ADPKD, and is in the process of working with a clinical trial team in Germany in order to do so.

“The goal is to do a larger trial that would hopefully once and for all nail down the effects of ketogenic diets on PKD.” – Thomas Weimbs, Biochemist, UC Santa Barbara

The scientists are also working with a team of dieticians in the US evaluating a program called Ren.Nu, which instructs patients that want to learn more about lifestyle changes and a ketogenic, plant-based, kidney-safe dietary approach.